Today, intravenous or I.V. solution administration sets are widely employed in infusing solutions directly into the veins of clinical patients. Typically, an administration set includes a flexible bag which is suspended at a height above the patient and which contains the solution to be administered. To feed the solution from the bag into the patient by gravity, a cannula is inserted into a sealed guide tube that extends downwardly out of the bottom of the bag. A feed tube extends from the cannula through a metering device, such as an adjustable clamp, to a needle that is injected into the patient. The cannula usually has a hollow prong or spike formed with one or more orifices which penetrates into the interior of the bag. The lower end of the spike extends down into a drip chamber where the solution drip or flow rate may be visibly observed.
Some medications that are administered through the use of I.V. administration sets of the type just described cannot be premixed. Others have a very short shelf life and thus may not be prepared substantially in advance of the time in which they are to be administered. In these situations it has been necessary to maintain medication ingredients segregated in separate containers in advance of and often during their administration. In a hospital environment this can be highly inefficient as where nurses or other hospital personnel have to mix solutions together in proper proportions at the time that they set up an administration set and connect it with a patient.
As a result of the foregoing, administration sets have heretofore been devised that have two compartments or chambers in which solutions or particulated fluids may be maintained separately in advance of their being mixed together at the time of administration. One type of these sets, as disclosed in U.S. Pat. No. 4,325,368, is constructed so that segregated liquids may be fed independently at mutually different rates into a common feed line without having to be premixed. Some mixing may inherently occur with this type of set, but only to a limited degree. In another type of administration set, such as that disclosed in U.S. Pat. Nos. 4,392,850 and 4,392,851, an in-line mixing procedure is made possible by which a sterile, powdered material such as freeze dried antibiotic may be mixed with a solvent. This type of in-line apparatus, however, is relatively complicated to manufacture and therefore expensive. With its compartments being in-line, one above the other, it is difficult to effect thorough mixing. Thus, they have had to be manually pumped and inverted for effective mixing. Even then such mixing remains difficult due to the fact that fluid communication between compartments is established only through an elongated, relatively narrow and restricted channel. Since many hospital personnel also do not have good mechanical dexterity, consistency in such preparations is difficult to obtain and to be relied upon.
It thus is seen that a need exists for apparatuses and methods of administering medications that overcomes the just described limitations of the prior art. It is to the provision of such, therefore, that the present invention is directed.